ht32bsx115 wrote:
  I seem to remember issues like the type of crankshaft and and rear main seal type compatibility and flywheel and then the flywheel housing (or bell-housing) .  (That's been hashed over many times over on iBoats and SEVERAL people have done that swap)
Manifolds, starter, alt mounting brackets will etc... fit both blocks.
The coupler and yoke should not be an issue.
Yep, in 85/86 GM switched from a 2 piece rear main seal to a 1 piece unit on the small block V8's.  Block casting at the rear was slightly different to accomodate this new seal arrangement, the crank was also different (although an adapter kit is available), as was the oil pan and flywheel as well.    Bellhousing should be the same - maybe just the coupler will be an issue, really depends on the style.   All other stuff is the same and interchangeable.